Self-supporting and hierarchical porous membrane of bacterial nanocellulose@metal-organic framework for ultra-high adsorption of Congo red.

The widespread use of synthetic dyes has serious implications for both the environment and human health. Therefore, there is an urgent need for the development of novel, high-efficiency adsorbents for these dyes. In this study, a Zirconium-based metal-organic framework (MOF) with controllable morphology was in-situ grown on bacterial nanocellulose (BC) via a solvothermal method. The resulting BC@MOF composite nanofibers have a high specific surface area of 651 m2/g and can be assembled into a self-supported porous membrane (BMMCa) through vacuum filtration with the assistance of calcium ions. The addition of Ca(II) significantly enhanced the mechanical properties of the membrane through dispersion effect and electrostatic interactions, as well as enhancing its adsorption performance through the salting-out effect. The BMMCa membrane, with its hierarchical porous structure and high flux, exhibits high selectivity for Congo red (CR) with an ultra-high adsorption capacity of 3518.6 mg/g. Furthermore, the self-supporting membrane achieved rapid and convenient removal of CR through circulating filtration adsorption. The adsorption mechanism and selectivity were verified through the molecular dynamics simulation calculations by Materials Studio (MS) software. This membrane-based adsorbent, with its ultra-high adsorption capacity, good selectivity, and recycling ability, has great potential for practical wastewater treatment applications.

New bacterial strains isolated from Tunisian biotopes: A sustainable enzymatic approach for decolorization and detoxification of Congo Red and Malachite Green.

Seven bacterial strains, isolated from various Tunisian biotopes, were investigated for Congo Red (CR) and Malachite Green (MG) decolorization. The isolated strains underwent morphological and biochemical tests, including assessments for antibiotic sensitivity as well as biofilm formation. One selected strain, ST11, was partially identified as Paenibacillus sp. strain ST11. The newly isolated crude bacterial filtrates (NICBFs) effectively decolorized CR and MG. Specifically, six and seven NICBFs were found to be effective for degrading CR (150 mg l-1) and MG (50 mg l-1), respectively. Under non-optimized conditions, CR and MG could be decolorized up to 80% within 6-12 h. The degradation products of CR and MG, characterized by UV-visible and FT-IR techniques, demonstrated both decolorization and transformation, highlighting the role of enzymes in dye degradation. Phytotoxicity and cytotoxicity studies evaluated the impact of treated and untreated CR and MG. Some NICBFs showed promise as powerful biological tools, reducing and sometimes detoxifying CR and MG, commonly used as fertilizers. The potential applications of these NICBFs in decolorization and bioremediation of dye-rich textile effluents were explored. The screening also identified environmentally friendly, cost-effective bacterial strains adaptable to various conditions through phytotoxicity and cytotoxicity studies.

Fabrication of eco-friendly nanocellulose-chitosan-calcium phosphate ternary nanocomposite for wastewater remediation.

Nanocomposites have emerged as promising materials for pollutant removal due to their unique properties. However, conventional synthesis methods often involve toxic solvents or expensive materials. In this study, we present a novel ternary nanocomposite synthesized via a simple, cost-effective vacuum filtration method. The composite consists of calcium phosphate (CaP), biowaste-derived nanocellulose (diameter <50 nm) (NC), and chitosan (CH). The nanocomposite exhibited exceptional pollutant removal capabilities due to the hybrid approach of combining adsorption and size exclusion that widens and accelerates pollutant removal. When tested with synthetic wastewater containing 10 ppm of Ni ions and 10 ppm of Congo red (CR) dye, it achieved impressive removal rates of 98.7% for Ni ions and 100% for CR dye. Moreover, the nanocomposite effectively removed heavy metals such as Cd, Ag, Al, Fe, Hg, Mo, Li, and Se at 100%, and Ba, Be, P, and Zn at 80%, 92%, 87%, and 97%, respectively, from real-world municipal wastewater. Importantly, this green nanocomposite membrane was synthesized without the use of harmful chemicals or complex modifications and operated at a high flux rate of 146 L/m2.h.MPa. Its outstanding performance highlights its potential for sustainable pollutant removal applications.

Isolation of chitosan and hydroxyapatite from waste edible white garden snail shells and their sensing applications towards industrial Congo red dye detection: Greener approach.

Biomaterials like chitosan, hydroxyapatite have been used in biomedical and pharmaceutical field, due to its valuable biochemical and physiological properties. In current work firstly our group has isolated a polysaccharide chitosan along with hydroxyapatite biomaterial from the same source by varying the process condition via greener approach. We have adapted greener approach for the isolation of chitosan within a short period of time and this is the very first report for the isolation of both chitosan and hydroxyapatite simultaneously from the same waste edible garden snail shells. Both these materials were thoroughly characterized by using UV, FT-IR, SEM techniques. Among synthetic colourants, congo red dye is recognized as carcinogens, which are usually used in the textile manufacturing. Interestingly, one of our biomaterial hydroxyapatite has shown good selectivity towards Congo red dye. The sensitivity range was obtained from 10 to 100 µM within the LOD of 101.52 nM. The developed sensor has been tested for various industrial effluents and shown good agreement with our results. Meanwhile these chitosan and hydroxyapatite have also been used as capping agent for the preparation of stable gold nanoparticles.

High efficiency of treated-phengite clay by sodium hydroxide for the Congo red dye adsorption: Optimization, cost estimation, and mechanism study.

Wastewater textile dye treatment is a challenge that requires the development of eco-friendly technology to avoid the alarming problems associated with water scarcity and health-environment. This study investigated the potential of phengite clay as naturally low-cost abundant clay from Tamgroute, Morocco (TMG) that was activated with a 0.1 M NaOH base (TMGB) after calcination at 850 °C for 3 h (TMGC) before its application in the Congo red (CR) anionic dye from the aqueous solution. The effect of various key operational parameters: adsorbent dose, contact time, dye concentration, pH, temperature, and the effect of salts, was studied by a series of adsorption experiments in a batch system, which affected the adsorption performance of TMG, TMGC, and TMGB for CR dye removal. In addition, the properties of adsorption kinetics, isotherms, and thermodynamics were also studied. Experimental results showed that optimal adsorption occurred at an acidic pH. At a CR concentration of 100 mg L-1, equilibrium elimination rates were 68%, 38%, and 92% for TMG, TMGC, and TMGB, respectively. The adsorption process is rapid, follows pseudo-second-order kinetics, and is best described by a Temkin and Langmuir isotherm. The thermodynamic parameters indicated that the adsorption of CR onto TMGB is endothermic and spontaneous. The experimental values of CR adsorption on TMGB are consistent with the predictions of the response surface methodology. These led to a maximum removal rate of 99.97% under the following conditions: pH = 2, TMGB dose of 7 g L-1, and CR concentration of 50 mg L-1. The adsorbent TMGB's relatively low preparation cost of around $2.629 g-1 and its ability to regenerate in more than 6 thermal calcination cycles with a CR removal rate of around 56.98%, stimulate its use for textile effluent treatment on a pilot industrial scale.

Studies on the potential risk of amyloidosis from exposure to cultured fibril from silk fibroin.

Amyloid A (AA) amyloidosis is induced by administering amyloid fibrils to animals under inflammatory conditions. Silk fibroin (SF), the main component of silk threads, forms amyloid-like fibrils and has been previously reported to induce AA amyloidosis in mice. In this study, SF was cultured in ethanol solution, and after confirming fibril formation through thioflavin T assay, Congo red assay, and observation under electron microscopy, cultured SF ethanol solutions were administered to mice via various routes to investigate the induction of target organs and amyloidosis. As a result, cultured SF ethanol solutions were confirmed to reach the lungs and spleen, but no amyloid deposition was observed. While SF forms amyloid-like fibril structures through cultivation in ethanol solution, its amyloid-enhancing factor (AEF) activity is considered low in mice.

Green reduction of ZnO nanoparticles using cationic dialdehyde cellulose (cDAC) for efficient Congo red dye removal.

More sustainable materials have been becoming an important concern of worldwide scientists, and cellulosic materials are one alternative in water decontamination. An efficient strategy to improve removal capacity is functionalizing or incorporating nanomaterials in cellulose-based materials. The new hybrid cDAC/ZnONPs was produced by green synthesis of zinc oxide nanoparticles (ZnONPs), promoting the in situ reduction and immobilization on the cationic dialdehyde cellulose microfibers (cDAC) surface to remove Congo red dye from water. cDAC/ZnONPs was characterized by scanning electron microscopy (SEM-EDS) and infrared spectroscopy (FTIR), which showed efficient nanoparticles reduction. Adsorption efficiency on cationic cellulose surface was investigated by pH, contact time, initial concentration, and dye selectivity tests. The material followed the H isotherm model, which resulted in a maximum adsorption capacity of 1091.16 mg/g. Herein, was developed an efficient and ecologically correct new adsorbent, highly effective in Congo red dye adsorption even at high concentrations, suitable for the remediation of contaminated industrial effluents.

Enhancing environmental sustainability: Butea monosperma leaves as a key component in WO3-based composites for water purification and therapeutic applications.

In this research, a novel nano-biocomposite material, namely, tungsten trioxide-Butea monosperma leaf powder (WO3@BLP), is an effective and eco-friendly adsorbent used for the mitigation of congo red (CR) and crystal violet (CV) dyes from its aqueous phase. The as-prepared WO3@BLP was characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), DLS analysis, and TGA. Many factors such as solution pH, WO3@BLP dose, temperature, contact time, and initial CR/CV dye concentrations were exploited to monitor the adsorption efficiency of WO3@BLP composites. The biosorption of both CR and CV dyes followed the Langmuir isotherm, with maximum adsorption capacities (qmax) reaching 84.91 mg g-1 for CR at pH 2.3 and 162.75 mg g-1 for CV at pH 8, fitting of kinetics data to the PSO model with closed values of qeexp (mg g-1) and qecal (mg g-1), i.e., 25.69 to 25.38 mg g-1 for CR dye and 29.06 to 29.08 mg g-1 for CV dye. The interaction mechanism behind the adsorption of CR and CV dyes onto the WO3@BLP bionanocomposite includes electrostatic interaction and surface complexation. The synthesized materials were tested for antifungal activity against three different Candida cells, i.e., C. albicans ATCC 90028, C. glabrata ATCC 90030, and C. tropicalis ATCC 750, by using broth dilution method on the minimum inhibiting concentration (MIC). Furthermore, the cytotoxicity of nano-formulated WO3@BLP was studied by in vitro hemolytic assay on a human host. Overall, this research presents a pioneering nano-biocomposite, WO3@BLP, as a sustainable adsorbent for CR and CV dye removal, adhering to Langmuir isotherm and pseudo-second-order kinetics. Its multifaceted approach includes elucidating interaction mechanisms, demonstrating antifungal activity, and assessing cytotoxicity, marking a significant advancement in environmental remediation.

Carbon dots as dual inhibitors of tau and amyloid-beta aggregation for the treatment of Alzheimer's disease.

Alzheimer's disease (AD) is the most common form of senile dementia, presenting a significant challenge for the development of effective treatments. AD is characterized by extracellular amyloid plaques and intraneuronal neurofibrillary tangles. Therefore, targeting both hallmarks through inhibition of amyloid beta (Aß) and tau aggregation presents a promising approach for drug development. Carbon dots (CD), with their high biocompatibility, minimal cytotoxicity, and blood-brain barrier (BBB) permeability, have emerged as promising drug nanocarriers. Congo red, an azo dye, has gathered significant attention for inhibiting amyloid-beta and tau aggregation. However, Congo red's inability to cross the BBB limits its potential to be used as a drug candidate for central nervous system (CNS) diseases. Furthermore, current studies only focus on using Congo red to target single disease hallmarks, without investigating dual inhibition capabilities. In this study, we synthesized Congo red-derived CD (CRCD) by using Congo red and citric acid as precursors, resulting in three variants, CRCD1, CRCD2 and CRCD3, based on different mass ratios of precursors. CRCD2 and CRCD3 exhibited sustained low cytotoxicity, and CRCD3 demonstrated the ability to traverse the BBB in a zebrafish model. Moreover, thioflavin T (ThT) aggregation assays and AFM imaging revealed CRCD as potent inhibitors against both tau and Aß aggregation. Notably, CRCD1 emerged as the most robust inhibitor, displaying IC50 values of 0.2 ± 0.1 and 2.1 ± 0.5 µg/mL against tau and Aß aggregation, respectively. Our findings underscore the dual inhibitory role of CRCD against tau and Aß aggregation, showcasing effective BBB penetration and positioning CRCD as potential nanodrugs and nanocarriers for the CNS. Hence, CRCD-based compounds represent a promising candidate in the realm of multi-functional AD therapeutics, offering an innovative formulation component for future developments in this area. STATEMENT OF SIGNIFICANCE: This article reports Congo red-derived carbon dots (CRCD) as dual inhibitors of tau and amyloid-beta (Aß) aggregation for the treatment of Alzheimer's disease (AD). The CRCD are biocompatible and show strong fluorescence, high stability, the ability to cross the blood-brain barrier, and the function of addressing two major pathological features of AD.

Insights into Transfer of Supramolecular Doxorubicin/Congo Red Aggregates through Phospholipid Membranes.

Doxorubicin (DOX) is a commonly used chemotherapeutic drug, from the anthracycline class, which is genotoxic to neoplastic cells via a DNA intercalation mechanism. It is effective and universal; however, it also causes numerous side effects. The most serious of them are cardiotoxicity and a decrease in the number of myeloid cells. For this reason, targeted DOX delivery systems are desirable, since they would allow lowering the drug dose and therefore limiting systemic side effects. Recently, synthetic dyes, in particular Congo red (CR), have been proposed as possible DOX carriers. CR is a planar molecule, built of a central biphenyl moiety and two substituted naphthalene rings, connected with diazo bonds. In water, it forms elongated ribbon-shaped supramolecular structures, which are able to selectively interact with immune complexes. In our previous studies, we have shown that CR aggregates can intercalate DOX molecules. In this way, they preclude DOX precipitation in water solutions and increase its uptake by MCF7 breast cancer cells. In the present work, we further explore the interactions between DOX, CR, and their aggregates (CR/DOX) with phospholipid membranes. In addition to neutral molecules, the protonated doxorubicin form, DXP, is also studied. Molecular dynamics simulations are employed to study the transfer of CR, DOX, DXP, and their aggregates through POPC bilayers. Interactions of CR, DOX, and CR/DOX with model monolayers are studied with Langmuir trough measurements. This study shows that CR may support the transfer of doxorubicin molecules into the bilayer. Both electrostatic and van der Waals interactions with lipids are important in this respect. The former promote the initial stages of the insertion process, the latter keep guest molecules inside the bilayer.

Structure Characterization and Dye Adsorption Properties of Modified Fiber from Wheat Bran.

The fibers from four wheat varieties (FT, XW 26, XW 45, and KW 1701) were selected and chemically modified with NaOH, epichlorohydrin, and dimethylamine to improve the adsorption capacity for anionic dye. The structure of the fibers with or without modification was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectrometry. The modified products were studied from the aspects of adsorption capacities, adsorption kinetics, and thermodynamics to provide a reference for the utilization of wheat bran. By SEM, more porous and irregular structures were found on the modified fibers. The XRD results showed that the crystals from the original fibers were destroyed in the modification process. The changes in fibers' infrared spectra before and after modification suggested that quaternary ammonium salts were probably formed in the modification process. The maximum adsorption capacity of wheat bran fibers for Congo red within 120 min was 20 mg/g for the unmodified fiber (XW 26) and 93.46 mg/g for the modified one (XW 45). The adsorption kinetics of Congo red by modified wheat bran fiber was in accord with the pseudo-second-order kinetic model at 40 °C, 50 °C, and 60 °C, indicating that the adsorption process might be mainly dominated by chemisorption. The adsorption was more consistent with the Langmuir isothermal adsorption model, implying that this process was monolayer adsorption. The thermodynamic parameters suggested that the adsorption occurred spontaneously, and the temperature increase was favorable to the adsorption. As mentioned above, this study proved that the wheat bran fiber could possess good adsorption capacities for anion dye after chemical modification.

Adsorption properties of cellulose-derived hydrogel and magnetic hydrogels from Sophora flavescens on Cu2+ and Congo red.

This study synthesized a robust, magnetically responsive hydrogel from Sophora flavescens-modified cellulose and chitosan, employing Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA and DTG), and scanning electron microscopy (SEM) to confirm the preservation of cellulose's intrinsic properties and the hydrogel's remarkable elasticity, toughness, and porosity. These hydrogels integrate cellulose's structural backbone with functional moieties from chitosan, enhancing adsorption capabilities for Cu2+ ions and Congo red (CR) dye. Kinetic and thermodynamic analyses reveal that adsorption is spontaneous and endothermic, following a pseudo-second-order model and the Freundlich isotherm. Notably, Cu2+ adsorption capacity increases with pH, while CR adsorption initially decreases before rising, demonstrating the hydrogels' potential as effective, sustainable adsorbents for removing pollutants from water.

The use of artificial neural network for modelling adsorption of Congo red onto activated hazelnut shell.

Activated hazelnut shell (HSAC), an organic waste, was utilized for the adsorptive removal of Congo red (CR) dye from aqueous solutions, and a modelling study was conducted using artificial neural networks (ANNs). The structure and characteristic functional groups of the material were examined by the FTIR method. The BET surface area of the synthesized material, named HSAC, was 812 m2/g. Conducted in a batch system, the adsorption experiments resulted in a notable removal efficiency of 87% under optimal conditions. The kinetic data for hazelnut shell activated carbon (HSAC) removal of CR were most accurately represented by the pseudo-second-order kinetic model (R2 = 0.998). Furthermore, the equilibrium data demonstrated a strong agreement with the Freundlich model. The maximum adsorption capacity of HSAC for CR was determined to be 34.8 mg/g. The optimum adsorption parameters were determined to be pH 6, contact time of 60 min, 10 g/L of HSAC, and a concentration of 400 mg/L for CR. Considering the various experimental parameters influencing CR adsorption, an artificial neural network (ANN) model was constructed. The analysis of the ANN model revealed a correlation of 98%, indicating that the output parameter could be reliably predicted. Thus, it was concluded that ANN could be employed for the removal of CR from water using HSAC.

Chitosan-loaded biogenic silver nanocomposite for photocatalytic remediation of dye pollutants and antibacterial activity.

The release of industrial wastewater has adverse effects on both aquatic ecosystems and the environment. Discharging untreated organic dyes into aquatic environments significantly amplifies pollution levels in these ecosystems. Ensuring the appropriate disposal of organic colorants and their derivatives before introducing them into wastewater streams is essential to prevent environmental contamination. This study aimed to develop an eco-friendly and sustainable approach to synthesize a chitosan-functionalized silver (Ag) nanocomposite using Solanum trilobatum for color pollutant mitigation. The synthesized CS-Ag nanocomposite was analyzed using various techniques such as UV-visible, FTIR, TEM, and EDS. TEM analysis revealed that the CS-Ag nanocomposite had a spherical nanostructure, with diameters ranging from 17.4 to 43.9 nm. These nanocomposites were tested under visible light irradiation to analyze their photocatalytic character against Congo red (CR). The nanocomposite exhibited a remarkable dye removal efficiency of over 93.6% within 105 min under irradiation. In the experimental recycling study, the CS-Ag nanocomposites demonstrated remarkable stability and reusability. Furthermore, the CS-Ag nanocomposite exhibited promising inhibition activity against bacterial pathogens. Our research revealed that the synthesized nanocomposite has the potential to act as a highly effective photocatalyst and bactericidal agent in various industrial and clinical applications.

Magnetic bio-composite based on zirconium and chitosan modified activated carbon from peanut husk with enhanced antibacterial and adsorptive potential for alizarin red and congo red in wastewater.

Creating new adsorbents is crucial for removing contaminants from water due to increased industrialization, which has worsened water pollution in recent years. In this study, a magnetic biocomposite, Zirconium (Zr)-doped chitosan (CS)-coated iron oxide nanoparticles (Fe3O4-NPs)-peanut husk (PH)-based activated carbon (AC) (Zr-CS/Fe3O4-NPs@PH-AC), was synthesized for efficient removal of alizarin red (AR) and congo red (CR) dyes, alongside antibacterial applications. Characterization via scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis revealed micropores and mesopores development due to chemical activation of PH biomaterial and Fe3O4-NPs addition. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) identified functional groups and structural properties. Vibrating sample magnetometry (VSM) analyzed magnetic properties. Optimal conditions for AR/CR removal were determined, including Zr-CS/Fe3O4-NPs@PH-AC dose, dye dose, contact time, and temperature, achieving maximum removal percentages. Experimentally determined maximum adsorption capacities for AR and CR were 374.3 and 154.1 mg·g-1, respectively. Cytotoxicity studies affirmed the eco-friendly and non-toxic nature of the adsorbent by exhibiting the reduction in the cell viability from 100 % to 88.68 % from the 0 to 200 µg·L-1 respectively. Additionally, the biocomposite exhibited significant antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) due to magnetic NPs. The material in this study shows extreme compatibility for numerous applications.

A facile green synthesis of manganese oxide nanoparticles using gum karaya polymer as a bioreductant for efficient photocatalytic degradation of organic dyes and antibacterial activity.

The release of organic dyes into water systems, mainly textile industries, poses a significant threat to human and animal health. This approach shows great potential for effectively removing harmful dyes and microorganisms from wastewater treatment for environmental remediation. This study utilized gum karaya polymer bio-reductant to synthesize manganese oxide (MnO2) nanoparticles through a green approach. The synthesized MnO2 nanoparticles were characterized and confirmed by various analytical techniques. These results revealed their nanoscale dimensions, morphology, chemical purity, crystal nature, decolorized intermediate, and band gap. The photocatalytic degradation of hazardous Congo red and methyl orange dyes using KRG-MnO2 nanoparticles under visible light irradiation. Furthermore, the results demonstrated that Congo red dye degradation efficiency of 93.34 % was achieved. The dye concentration (8 to 16 mg/L), pH concentration, and radical trapping were studied. This suggests that holes and hydroxyl radicals play a crucial role in degrading the Congo red dye and demonstrate superior recyclability after three successive cycles and good stability. The possible intermediates from the Congo red dye degradation were identified through LC-MS analysis. The polymer composite MnO2 NPs have displayed notable antibacterial activity against pathogenic bacteria such as Staphylococcus aureus and Escherichia coli. The research indicates that MnO2 nanoparticles functionalized with polymers can efficiently remove pathogens and organic dyes from diverse industrial water treatment processes.

Green synthesis of zinc oxide nanoparticles from Sida acuta leaf extract for antibacterial and antioxidant applications, and catalytic degradation of dye through the use of convolutional neural network.

This study synthesized zinc oxide nanoparticles (ZnO NPs) using a novel green approach, with Sida acuta leaf extract as a capping and reducing agent to initiate nucleation and structure formation. The innovation of this study lies in demonstrating the originality of utilizing zinc oxide nanoparticles for antibacterial action, antioxidant potential, and catalytic degradation of Congo red dye. This unique approach harnesses eco-friendly methods to initiate nucleation and structure formation. The synthesized nanoparticles' structure and conformation were characterized using UV-vis (λmax = 280 nm), X-ray, atomic force microscopy, SEM, HR-TEM and FTIR. The antibacterial activity of the Nps was tested against Pseudomonas sp, Klebsiella sp, Staphylococcus aureus, and E. coli, demonstrating efficacy. The nanoparticles exhibited unique properties, with a crystallite size of 20 nm (XRD), a surface roughness of 2.5 nm (AFM), and a specific surface area of 60 m2/g (SEM). A Convolutional Neural Network (CNN) was effectively employed to accurately classify and analyze microscopic images of green-synthesized zinc oxide nanoparticles. This research revealed their exceptional antioxidant potential, with an average DPPH scavenging rate of 80% at a concentration of 0.05 mg/mL. Additionally, zeta potential measurements indicated a stable net negative surface charge of approximately -12.2 mV. These quantitative findings highlight the promising applications of green-synthesized ZnO NPs in healthcare, materials science, and environmental remediation. The ZnO nanoparticles exhibited catalytic capabilities for dye degradation, and the degradation rate was determined using UV spectroscopy. Key findings of the study encompass the green synthesis of versatile zinc oxide nanoparticles, demonstrating potent antibacterial action, antioxidant capabilities, and catalytic dye degradation potential. These nanoparticles offer multifaceted solutions with minimal environmental impact, addressing challenges in various fields, from healthcare to environmental remediation.

Kinetic studies on optimized extracellular laccase from Trichoderma harzianum PP389612 and its capabilities for azo dye removal.

BACKGROUND: Azo dyes represent a common textile dye preferred for its high stability on fabrics in various harsh conditions. Although these dyes pose high-risk levels for all biological forms, fungal laccase is known as a green catalyst for its ability to oxidize numerous dyes. METHODS: Trichoderma isolates were identified and tested for laccase production. Laccase production was optimized using Plackett-Burman Design. Laccase molecular weight and the kinetic properties of the enzyme, including Km and Vmax, pH, temperature, and ionic strength, were detected. Azo dye removal efficiency by laccase enzyme was detected for Congo red, methylene blue, and methyl orange. RESULTS: Eight out of nine Trichoderma isolates were laccase producers. Laccase production efficiency was optimized by the superior strain T. harzianum PP389612, increasing production from 1.6 to 2.89 U/ml. In SDS-PAGE, purified laccases appear as a single protein band with a molecular weight of 41.00 kDa. Km and Vmax values were 146.12 µmol guaiacol and 3.82 µmol guaiacol/min. Its activity was stable in the pH range of 5-7, with an optimum temperature range of 40 to 50 °C, optimum ionic strength of 50 mM NaCl, and thermostability properties up to 90 °C. The decolorization efficiency of laccase was increased by increasing the time and reached its maximum after 72 h. The highest efficiency was achieved in Congo red decolorization, which reached 99% after 72 h, followed by methylene blue at 72%, while methyl orange decolorization efficiency was 68.5%. CONCLUSION: Trichoderma laccase can be used as an effective natural bio-agent for dye removal because it is stable and removes colors very well.

Bio-based composite from chitosan waste and clay for effective removal of Congo red dye from contaminated water: Experimental studies and theoretical insights.

Water pollution due to dyes in the textile industry is a serious environmental problem. During the finishing stage, Congo red (CR) dye, water-soluble, is released into wastewater, polluting the water body. This study explores the effectiveness of utilizing a composite composed of Safi raw clay and chitosan to remove an anionic dye from synthetic wastewater. The chitosan was extracted from crab shells. Its removal performance was compared to that of natural clay. Both the composite and raw clay were used to remove target pollutant. The effects of the chitosan load in the composite, size particles, initial dye concentration, contact time, pH, and temperature on the dye's elimination were tested in batch modes. The composite with 30% (w/w) of chitosan exhibited the highest dye removal. At pH 2, an adsorption capacity of 84.74 mg/g was achieved, indicating that the grafting of the polymer onto clay surface enhances its efficacity and stability in acidic environments. This finding was supported by characterization data obtained from X-ray diffraction (XRD), scanning electron microscopy (SEM), dispersive X-ray spectroscopy (EDX), and Fourier transform infrared (FT-IR) analyses. Under optimized conditions of 20 mg dose, pH 2, 30 min of reaction time, and 20 mg/L of dye concentration, about 92% of dye removal was achieved. The Langmuir isotherm model represents dye adsorption by the composite, while dye removal was controlled by pseudo-second-order model. Thermodynamic data of the adsorption (ΔH = +8.82 kJ/mol; ΔG <0) suggested that the dye adsorption was spontaneous and endothermic. The findings provide insights into the dye elimination by the adsorbent, indicating that the removal occurred via attractive colombic forces, as confirmed by density functional theory (DFT) analysis. Overall, the composite of natural clays and chitosan waste is a promising and innovative adsorbent for treating wastewater containing recalcitrant dyes.

Red emissive fluorescent carbon dots based on ternary carbon source for imaging α-synuclein fibrils.

The misfolding and aggregation of α-synuclein monomers usually cause the occurrence and development of Parkinson's disease (PD). It is important to develop effective methods for detection of α-synuclein aggregates. Carbon dots (CDs) could be the potential fluorescence probe for this purpose owing to their appreciated optical properties. However, undefined structure of CDs and complicated three-dimensional structure of protein severely hindered the design of fluorescence probe towards protein aggregates. Herein, a red emissive fluorescent amphiphilic CD, named as CL-9, was designed with a high sensitivity to α-synuclein fibrils by a one-step heating process, using the ternary carbon source, including Congo red, l-tryptophan and urea. The CL-9 exhibited turn-on red emissive fluorescence towards α-synuclein fibril, but remained no change towards its monomer. Compared with the original Congo red dye, CL-9 exhibited stronger turn-on red fluorescence towards α-synuclein fibrils with better anti-photobleaching resistance, biocompatibility and signal-to-noise ratio. The CL-9 was successful as a fluorescent probe to image α-synuclein fibrils in NL-5901 C. elegans. The present study provided a feasible approach using the multiple carbon sources to construct the CDs based fluorescence probe targeting amyloid proteins.